Buffer pre-activation for electrochromic device

ABSTRACT

An electrochromic device, system using, and method for, which may pre-activate a buffer is disclosed. The electrochromic device may comprise a first substrate, a second substrate, a first electrode, a second electrode, and an electrochromic medium. The second substate may be disposed in apart relationship with the first substrate. The first and second electrodes may be associated with the first and second substrates, respectively. The electrochromic medium may be disposed between the first and second electrodes. Further, the electrochromic medium may comprise electrochromic materials and a redox buffer. Each of the electrochromic materials and the buffer may be operable between activated and deactivated states. The electrochromic device may be configured to apply a voltage to substantially pre-activate the buffer and hold the buffer in this state prior to substantially activating the electrochromic materials, thereby decreasing the response time of the electrochromic device upon activation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 62/969,359 filed on Feb. 3, 2020, entitled“BUFFER PRE-ACTIVATION FOR ELECTROCHROMIC DEVICE,” the disclosure ofwhich is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present invention relates in general to electrochromic devices and,more particularly, to operating electrochromic devices having anelectrochromic solution comprising one or more buffer and one or moreelectrochromic material.

BACKGROUND OF INVENTION

Electrochromic devices have been well known for many years. When asufficient electrical potential is applied across a pair of electrodes,an electrochromic medium, disposed between the electrodes, may becomeactivated, changing its color and/or light transmissivity. Takingadvantage of this, devices such as dimmable mirrors and windows havebecome increasingly popular the automotive and aviation industries.

However, during normal operation, electrochromic media sometimes do notadequately return to a predetermined state. In some instances—even inthe absence of an electrical potential—anodic and cathodic materials ofthe electrochromic materials may oxidize or reduce, respectively. Thisoxidation or reduction of the electrochromic medium may be undesirable.This undesirable oxidation or reduction may be caused by undesirableelectrochromic medium impurities, exposure of the electrophilic mediumto the external atmosphere, and/or long-term weathering of theelectrochromic device.

To mitigate issues associated with returning the electrochromic mediumto a predetermined state and preventing undesirable coloration, redoxbuffers are implemented. These redox buffers are combined with theelectrochromic medium to form an electrochromic solution. However, whenthe electrical potential is applied to the electrochromic solution,these buffers may slow down the darkening of an electrochromic device.Accordingly, there is a need for an improved system for using buffers inan electrochromic device that eliminates or reduces the reduction indarkening time caused by the buffer. When an imbalance of anodicoxidation and cathodic reduction occurs, an undesirable electrochromicmedium coloration may manifest in the electrochromic device.

SUMMARY

In accordance with the present disclosure, the disadvantages andproblems associated with electrochromic devise incorporating buffers inthe past are eliminated or reduced.

In accordance with one aspect of the present disclosure, a device isdisclosed. The device may comprise a first substrate, a secondsubstrate, a first electrode, a second electrode, and an electrochromicmedium is disclosed. The first substate may have a first surface and asecond surface. Similarly, the second substate may have a third surfaceand a fourth surface. Further, the second substate may be disposed in aspaced-apart relationship with the first substrate such that the secondand third surfaces face one another. The first electrode may be disposedon the second surface. The second electrode may be disposed on the thirdsurface. The electrochromic medium may be disposed between the first andsecond electrodes. Further, the electrochromic medium may compriseelectrochromic materials and a redox buffer. The electrochromicmaterials and the buffer ma each be operable between activated anddeactivated states.

The first and second electrodes may be operable to operable to: initiatea first voltage, hold the first voltage, initiate a second voltage, andhold the second voltage. The first voltage may be operable tosubstantially activate the buffer. In some embodiments, the firstvoltage is not operable to substantially activate the electrochromicmaterials. Holding the first voltage may be operable to maintain thesubstantial buffer activation. The second voltage may be greater thanthe first voltage in magnitude and have the same polarity as the firstvoltage. Further, the second voltage may be operable to substantiallyincrease the degree of activation of the electrochromic materials.Holding the second voltage may be operable to maintain the increasedelectrochromic material activation.

In some embodiments, the first and second electrodes may be furtheroperable to: initiate a third voltage, hold the third voltage, initiatea fourth voltage, and hold the fourth voltage. The third voltage may beopposite in polarity relative the first and second voltages holding thethird voltage may be operable to substantially de-activate theelectrochromic materials. In some of these embodiments, the first andthird voltages may be equal in absolute magnitude. The fourth voltagemay be of the same polarity as the first and second voltages. Further,the fourth voltage may be operable to substantially activate the buffer.In some of these embodiments, the fourth voltage may be substantiallyequal to the first voltage. Further, the fourth voltage may not beoperable to substantially activate the electrochromic materials. Holdingthe fourth voltage may be operable to maintain the buffer in asubstantially activated state.

In other embodiments, the first and second electrodes may be furtheroperable to: initiate a third voltage and hold a third voltage. Thethird voltage may be operable to substantially change the degree ofactivation of the electrochromic materials. Further, the third voltagemay be different from the first voltage. Holding the third voltage maybe operable to maintain activation of the electrochromic materials. Insome of these embodiments, the first and second electrodes may be evenfurther operable to: initiate a fourth voltage, hold the fourth voltage,initiate a fifth voltage, and hold the fifth voltage. The fourth voltagemay be opposite in polarity relative the first, second, and thirdvoltages. Holding the fourth voltage may be operable to substantiallyde-activate the electrochromic materials. The fifth voltage may be ofthe same polarity as the first, second, and third voltages. Further, thefifth voltage may be operable to substantially activate the buffer. Insome of these embodiments, the fifth voltage may not be operable tosubstantially activate the electrochromic materials. Holding the fifthvoltage may be operable to maintain the buffer in an activated state.

In yet other embodiments, the device may be associated with a vehicle.Further, the device may be operable to receive a signal from a sensorassociated with the vehicle. The sensor may be further associated withthe device. In some of these embodiments, the sensor may be an imager.The sensor may correspond to the detection of a standby triggeringcondition by the sensor. In some of these embodiments, the standbytriggering condition may be the occupancy of the vehicle. The first andsecond electrodes may accordingly be further operable to initiate thefirst voltage based, at least in part, on the detection of the standbytriggering condition. Additionally or alternatively, the device may beoperable to substantially deactivate the buffer when the signal is nolonger received.

In yet other embodiments, the device may be associated with a vehicle.Further, the device may be operable to receive a signal from a sensorlikewise associated with the vehicle. The signal may correspond to thedetection of a hibernation triggering condition by the sensor. The firstand second electrodes may accordingly be further operable tosubstantially stop voltage application to the electrochromic mediumbased, at least in part, on the received signal.

In accordance with another aspect of the present disclosure, a method isdisclosed. The method may comprise the steps of initiating a firstvoltage, holding the first voltage, initiating a second voltage, andholding the second voltage. The first voltage may be applied to anelectrochromic medium. The electrochromic medium may compriseelectrochromic materials and a redox buffer. The electrochromicmaterials and buffer may each be electroactive and operable betweensubstantially activated and deactivated states. The first voltage may beoperable to substantially activate the buffer and not substantiallyactivate the electrochromic materials. Holding the first voltage isoperable to maintain the buffer in a substantially activated state. Thesecond voltage may likewise be applied to the electrochromic medium. Thesecond voltage may be operable to substantially increase the degree ofthe activation of the electrochromic materials. Further, the secondvoltage may be greater than the first voltage. Holding the secondvoltage may be operable to maintain the increased activation of theelectrochromic materials.

In some embodiments, the method may further comprise the steps oflowering the second voltage to a third voltage, holding the thirdvoltage, increasing the third voltage to a fourth voltage, and holdingthe fourth voltage. The third voltage may be opposite in sign relativethe first and second voltages. Holding the third voltage may be operableto substantially de-activate the electrochromic materials. The fourthvoltage may be of the same sign as the first and second voltages.Further, the fourth voltage may be operable to substantially activatethe buffer and not substantially activate the electrochromic materials.Holding the fourth voltage may be operable to maintain the buffer in asubstantially activated state.

In accordance with yet another aspect of the present disclosure, asystem is disclosed. The system may comprise an electrochromic deviceand a controller. The electrochromic device may comprise anelectrochromic medium. The electrochromic medium may compriseelectrochromic materials and a redox buffer. The controller may beoperable to: initiate a first voltage, hold the first voltage, initiatea second voltage, and hold the second voltage. The first voltage may beapplied across the electrochromic medium. Further, the first voltage maybe operable to substantially activate the buffer. Holding the firstvoltage may be operable to substantially maintain the buffer activation.The second voltage may be applied across the electrochromic medium.Further, the second voltage greater than the first voltage and operableto substantially increase an activation state of the electrochromicmaterials. Holding the second voltage may be operable to maintain theincreased activation of the electrochromic materials.

In some embodiments, the system may further comprise a first sensor. Thefirst sensor may be operable to detect a standby triggering condition.The standby triggering condition may be at least one of a vehiclestarting and a vehicle occupancy. Accordingly, the controller may befurther operable to receive a signal from the sensor. The signal maycorrespond to the detection of the standby triggering condition.Further, based, at least in part, on the detection of the standbytriggering condition, the controller may initiate the first voltage.

In some such embodiments, at least one of the first sensor and a secondsensor are operable to detect a hibernation triggering condition.Accordingly, the controller may be further operable to receive a secondsignal from the at least one of the first sensor and the second sensor.The second signal may correspond to the detection of the hibernationtriggering condition. Further, based, at least in part, on the receiptof the second signal, the controller may initiate a third voltage. Thethird voltage may be operable to substantially deactivate the buffer.

The advantages of certain embodiments of the present disclosure includea faster and more responsive electrochromic device. Application of abuffer pre-activation voltage partially activates the electrochromicsolution, such that the buffer is fully activated prior to a desiredchange in electrochromic device transmittance. Accordingly, when anelectrical potential is applied to change electrochromic devicetransmittance, the buffer will not have increased consumption of theelectrical current, because the buffer is already activated, andtherefore allow the electrochromic materials to consumer a greateramount of this current and thereby activate faster, increasing the speedof transmittance change.

These and other aspects, objects, and features of the present disclosurewill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings. Itwill also be understood that features of each embodiment disclosedherein may be used in conjunction with, or as a replacement for,features in other embodiments.

BRIEF DESCRIPTION OF FIGURES

In the drawings:

FIG. 1 a: An embodiment of an electrochromic device.

FIG. 1 b: An embodiment of an electrochromic device.

FIG. 1 c: An embodiment of an electrochromic device.

FIG. 2: A cross-sectional schematic representation of an electrochromicdevice.

FIG. 3: A process flowchart for managing an electrochromic device withbuffer pre-activation.

FIG. 4a : A process flowchart for operating an electrochromic devicewith buffer pre-activation.

FIG. 4b : A schematic graph of process voltages.

FIG. 5: A schematic graph of electrochromic medium transmission as afunction of applied voltage.

FIG. 6: A schematic graph comparing light transmission as a function oftime with and without buffer pre-activation.

FIG. 7: A schematic graph of the absolute rate of change in transmissionof an electrochromic solution as a function of time.

DETAILED DESCRIPTION

For the purposes of description herein, it is to be understood that thespecific devices and processes illustrated in the attached drawings anddescribed in this disclosure are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificcharacteristics relating the embodiments disclosed herein are not to beconsidered as limiting, unless the claims expressly state otherwise.

The present disclosure is directed to an electrochromic device withand/or method for, buffer pre-activation. Electrochromic devicesgenerally comprise an electrochromic medium, the electrochromic mediummay contain a solvent, one or more electrochromic materials, and/or abuffer. The buffer may be a redox buffer. Generally, to act as a redoxbuffer, a buffer may exhibit a redox potential in the range bound by ananodic oxidation potential and a cathodic reduction potential of theelectrochromic materials. Accordingly, the buffer may be activated at alower electrical potential than the electrochromic materials. Therefore,when the electrochromic device applies an electrical potential to theelectrochromic solution, the buffer may slow the change in transmittanceof the electrochromic device. This is because the buffer may consumeelectrical current, thus reducing the available electrical current foractivation of the electrochromic materials. This reduction in availablecurrent may increase the time required to activate the electrochromicmaterials. Also, generally, the buffer is preferably activated over theelectrochromic medium due to its lower activation potential, therebyincreasing a lag time in electrochromic activation.

This disclosure relies on applying a buffer pre-activation voltage toreduce and/or eliminate this lag time. A voltage is a measure of anelectromotive force or electrical potential. The buffer pre-activationvoltage may be initiated to pre-activate the buffer beforeelectrochromic device darkening is desired. The buffer pre-activationvoltage may be equal to the activation potential of the buffer. Further,the buffer pre-activation voltage may be held to maintain the buffer'sactivation. This may produce a buffer activated stand-by state of theelectrochromic medium, ready for immediate activation of theelectrochromic materials. To activate the electrochromic materials, theapplied voltage may be increased from the buffer pre-activation voltageto an electrochromic activation voltage corresponding to a desireddegree of electrochromic activation. This electrochromic activationvoltage may be held for the duration of the desired electrochromicactivation. As a result, a faster and more responsive electrochromicdevice may be achieved.

Additionally, the present disclosure is also directed to thedeactivation of the electrochromic materials. Once electrochromicmaterial activation is no longer desired, the buffer may be returned toits standby state wherein the buffer is pre-activated. Accordingly, onceelectrochromic material activation is no longer desired, theelectrochromic activation voltage may be decreased to an electrochromicdeactivation voltage, thereby speeding up the deactivation of theelectrochromic medium by removing electrons. The electrochromicdeactivation voltage may be substantially equal to the negative of thebuffer pre-activation voltage. Further, the electrochromic deactivationvoltage may be held to maintain the electrochromic materials'deactivation process. Once the electrochromic materials are sufficientlydeactivated, the voltage may be increased to the buffer pre-activationvoltage and held, rapidly returning the electrochromic solution anddevice to a standby state. As a result, the electrochromic device may bemore rapidly returned to its pre-activated standby state than: if thevoltage is simply returned to the buffer pre-activation voltage, if theelectrodes are shorted, or if the electrodes are left in open circuitconfiguration.

FIGS. 1a-c illustrate particular embodiments of an electrochromicdevice. In some embodiments, as shown in FIG. 1 a, an automobile 100 maycomprise one or more electrochromic device in the form of a window 10,an external rear-view mirror 11, and/or an interior rear-view mirror 15.FIG. 1b illustrates another particular embodiment of an electrochromicdevice. In this embodiment, an airplane 120 comprises one or moreelectrochromic device in the form of a window 10. FIG. 1c illustratesyet another particular embodiment of an electrochromic device. In thisembodiment, a building 130 may comprise one or more electrochromicdevice in the form of a window 10.

Window 10 may be a device configured to provide a physical barrierbetween two areas and be operable to allow the variable transmission oflight between the two areas. Window 10 may come in many configurations.For example, window 10 may be in the form of a building window, avehicle windshield, a vehicle side window, a vehicle rearview window, ora sunroof.

External rear-view mirror 11 may be a device coupled to an automobileexterior configured to provide a viewer with a field of view comprisingan exterior, to the rear or the side, of automobile 10. Further,interior rear-view mirror 11 may also be variably transmissive tominimize glare.

Interior rear-view mirror 13 may be a device, in an automobile interior,configured to provide a viewer with a field of view comprising arearward exterior of automobile 10. Further, interior rear-view mirror13 may also be variably transmissive to minimize glare.

FIG. 2 is a cross-sectional schematic representation of anelectrochromic device 200. Electrochromic device 200, for example, maybe a mirror, a window, a display device, a contrast enhancement filter,and the like. Further, FIG. 2 is merely a schematic representation ofelectrochromic device 200, and as such, some of the components have beendistorted from their actual scale for pictorial clarity. Electrochromicdevice 200 may comprise: a first substrate 210, a second substrate 220,a first electrode 230, a second electrode 240, a seal 250, a chamber260, and/or an electrochromic medium 270. Additionally, electrochromicdevice 200 may be operable between a substantially activated state and asubstantially un-activated state. Operation between such states maycorrespond to a variable transmissivity of electrochromic device 200.

First substrate 210 may be substantially transparent in the visibleand/or infrared regions of the electromagnetic spectrum. Further, firstsubstrate 210 may have a first surface 211 and a second surface 212.First surface 211 and second surface 212 may be disposed opposite oneanother with second surface 212 disposed in a first direction relativefirst surface 210. The first direction may additionally be defined assubstantially orthogonal the first and second surfaces 211, 212.Additionally, first substrate 210, for example, may be fabricated fromany of a number of materials, such as alumino-silicate glass, such asFalcon commercially available from AGC; boroaluminosilicate (“BAS”)glass; polycarbonate, such as ProLens® polycarbonate, commerciallyavailable from Professional Plastics, which may be hard coated;polyethylene terephthalate, such as but not limited to Spallshield® CPETavailable from Kuraray®; soda lime glass, such as ultra-clear soda limeglass; float glass; natural and synthetic polymeric resins and plastics,such as polyethylene (e.g., low and/or high density), polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC),polysulfone, acrylic polymers (e.g., poly(methyl methacrylate) (PMMA)),polymethacrylates, polyimides, polyamides (e.g., a cycloaliphaticdiamine dodecanedioic acid polymer (i.e., Trogamid® CX7323)), epoxies,cyclic olefin polymers (COP) (e.g., Zeonor 1420R), cyclic olefincopolymers (COC) (e.g., Topas 6013S-04 or Mitsui Apel),polymethylpentene, cellulose ester based plastics (e.g., cellulosetriacetate), transparent fluoropolymer, polyacrylonitrile; and/orcombinations thereof. While particular substrate materials aredisclosed, for illustrative purposes only, numerous other substratematerials are likewise suitable—so long as the materials are at leastsubstantially transparent and exhibit appropriate physical propertiessuch as strength and tolerance to conditions of the device'senvironment, such as ultra-violet light exposure from the sun, humidity,and temperature extremes.

Similarly, second substrate 220 may, have a third surface 223 and afourth surface 224. Third surface 223 and fourth surface 224 may bedisposed opposite one another with fourth surface 224 disposed in thefirst direction relative third surface 223. Additionally, secondsubstrate 220 may be disposed in the first direction in a spaced apartrelationship relative first substate 210. Thus, third surface 223 mayface second surface 212. In some embodiments, second substrate 220 maybe substantially transparent in the visible and/or infrared regions.Accordingly, second substrate 220 may be comprised of the same orsimilar materials suitable for first substate 210. In other embodiments,such as for a rearview mirror assembly, substantial transparency is notnecessary. In such an embodiment, second substrate 220 may also beselected from substantially opaque and/or reflective materials.

First electrode 230 is an electrically conductive material. Further,first electrode 230 may be associated with second surface 212.Accordingly, first electrode 230 may be disposed on second surface 212.The electrically conductive material of first electrode 230 may besubstantially transparent in the visible and/or infrared regions of theelectromagnetic spectrum, bond reasonably well to first substrate 210,and/or be generally resistant to corrosion from materials of chambermaterial 270. For example, the electrically conductive material may befabricated from a transparent conductive oxide (TCO), such as fluorinedoped tin oxide (FTO), tin doped indium oxide (ITO), doped zinc oxide,indium zinc oxide, or other materials known in the art.

Second electrode 240 is, likewise, an electrically conductive material.Further, second electrode 240 is associated with third surface 223.Accordingly, second electrode 240 may be disposed on third surface 132.The electrically conductive material may be fabricated from the same orsimilar materials as first electrode 230. Accordingly, in someembodiments, second electrode 240 may be substantially transparent inthe visible and/or infrared regions. In other embodiments, such as thosewhere electrochromic devices 200 is a mirror, substantial transparencyis not necessary. In such an embodiment, second electrode 240 may beselected from substantially opaque and/or reflective materials.Accordingly, in some embodiments, second electrode 240 may comprise areflective coating. Typical coatings for this type of reflector includechromium, rhodium, ruthenium, silver, and combinations thereof.

Seal 250 may be disposed in a peripheral manner to, at least in part,define a chamber 260. Chamber 260 is disposed between first substrate210 and second substrate 220. Accordingly, chamber 260 may be defined byseal 250 in conjunction with at least two of: first substrate 210,second substrate 220, first electrode 230, and second electrode 240. Insome embodiments, chamber 260 may, more specifically, be defined by seal250, first electrode 230, and second electrode 240. Seal 250 maycomprise any material capable of being bonded to the at least two of:first substrate 210, second substrate 220, first electrode 230, andsecond electrode 240, to in turn inhibit oxygen and/or moisture fromentering chamber 260, as well as inhibit electrochromic medium 270 frominadvertently leaking out. Seal 250, for example, may include epoxies,urethanes, cyanoacrylates, acrylics, polyimides, polyamides,polysulfides, phenoxy resin, polyolefins, and silicones. In someembodiments, seal 250 may bridge across and extend about peripheries ofthe first and second substrates 210, 220. In other embodiments, seal250, is disposed between the first and second substrates 210, 220 in aperipheral manner. Further, seal 250 may extend all the way to thesecond and/or third surfaces 212, 223. In such an embodiment, the firstand/or second electrodes 230, 240 may be partially removed where seal250 is positioned. Alternatively, seal 250 my terminate at and/or extendbetween the first and second electrodes 230, 240.

Electrochromic medium 270 may be disposed in chamber 260. Accordingly,the electrochromic medium 270 may be disposed between the first andsecond electrodes 230, 240. In some embodiments, electrochromic medium270 may be a solution. Accordingly, electrochromic medium 270 maycomprise one or more solvent. Further, electrochromic medium 270 maycomprise one or more electrochromic materials and/or a buffer. Each ofthe electrochromic materials and the buffer may be operable betweensubstantially un-activated and substantially activated states. Further,the electrochromic materials may be electroactive anodic and cathodicmaterials that upon activation, due to the application of an electronicvoltage or potential, exhibit a change in absorbance at one or morewavelengths of the electromagnetic spectrum. The change in absorbancemay occur in the visible region of the electromagnetic spectrum. In someembodiments, the electrochromic materials may be disposed in one or morelayers associated with the first and/or second electrodes 230, 240. Inother embodiments, the electrochromic materials may be in solution.Accordingly, the electrochromic materials may be dissolved in thesolvent. The buffer may be a redox buffer. In some embodiments, thebuffer may be in solution. Accordingly, the buffer may be dissolved in asolvent. Further, the buffer may be chosen such that the buffer exhibitsa redox potential in a range bound by an anodic oxidation potential anda cathodic reduction potential of the electrochromic materials. Theelectrochromic medium and the redox buffer may be fabricated from anyone of a number of materials, including, for example, those disclosed inU.S. Pat. No. 6,433,914, entitled “COLOR-STABILIZED ELECTROCHROMICDEVICES;” U.S. Pat. No. 6,697,185, entitled “COLOR-STABILIZEDELECTROCHROMIC DEVICES;” and U.S. Pat. No. 4,902,108, entitled“SINGLE-COMPARTMENT, SELF-ERASING, SOLUTION-PHASE ELECTROCHROMICDEVICES, SOLUTIONS FOR USE THEREIN, AND USES THEREOF,” the entireties ofwhich are herein incorporated by reference.

Additionally, the solvent may compromise any of a number of common,commercially available solvents including 3-methylsulfolane,glutaronitrile, dimethyl sulfoxide, dimethyl formamide, acetonitrile,tetraglyme and other polyethers, alcohols such as ethoxyethanol,nitriles, such as 3-hydroxypropionitrile, 2-methylglutaronitrile,ketones including 2-acetylbutyrolactone, cyclopentanone, cyclic estersincluding beta-propiolactone, gamma-butyrolactone, gamma-valerolactone,propylene carbonate, ethylene carbonate and homogenous mixtures of thesame. While specific solvents have been disclosed as being associatedwith the electrochromic medium 270, numerous other solvents that wouldbe known to those having ordinary skill in the art may be used.

Electrochromic device 200 may be operable to vary its transmissivity. Tovary the transmissivity, the first and second electrodes 230, 240 mayoperate to deliver an electrical potential across chamber 260.Therefore, the first and second electrodes 230, 240 may operate to applyan electrical potential to electrochromic medium 270. Accordingly, theelectrochromic materials may become substantially activated. Activationof the electrochromic materials may correspond to the oxidation andreduction of the anodic and cathodic materials, respectively. Theactivation of the electrochromic materials may be to various degrees.The degree of activation may correspond to the percentage of anodic andcathodic materials that are activated. Further, via various degrees ofactivation, electrochromic medium 270 may be variably transmissive. Insome embodiments, as the electrochromic materials are increasinglyactivated, the transmissivity may decrease. Accordingly, electrochromicmedium 270 and thus electrochromic device 200 may increasingly darken.Conversely, as the electrochromic materials are decreasingly activated,the transmissivity may increase.

During electrochromic activation, the buffer may slow the activation ofthe electrochromic materials. The electrical potential introducescurrent to electrochromic medium 270. The redox buffer may initiallyconsume the current to a greater extent than the electrochromicmaterials, due to its redox potential being bound by the electrochromicmaterials' respective oxidation and reduction potentials. This may occurto some extent until the buffer has become fully activated. Accordingly,the first and second electrodes 230, 240 are operable to apply a bufferpre-activation voltage. The buffer pre-activation voltage may beoperable to substantially activate the buffer, but not substantiallyactivate the electrochromic materials. Accordingly, the electrochromicmaterials my exhibit an activation percentage of less than or equal to20, 15, 10, 5, 4, 3, 2, or 1 percent due to application of the bufferpre-activation voltage.

Further, electrochromic device 200 may be manually or automaticallyoperated. When in manual operation, user may operate a user interface toselect a level of transmittance for electrochromic device 200. When inautomatic operation, circuitry and one or more sensor may be utilized tosense light and communicate a light condition to a controller. Thecontroller may comprise a memory and a processor. The memory may beoperable to store one or more algorithm. The algorithm may by operableto determine an appropriate level of transmittance for the lightcondition and regulate the electrical voltage applied to the first andsecond electrodes 230, 240 accordingly. The processor may be operable toexecute the algorithm.

Embodiments of the present disclosure may have the advantage of a fasterand more responsive electrochromic device 200. Application of a bufferpre-activation voltage may partially activate electrochromic medium 270,such that the buffer is substantially or fully activated prior to adesired change in electrochromic device 200 transmittance. Accordingly,when an electrical potential is applied to change electrochromic device200 transmittance, presence of the redox buffer will not initiallyconsume additional current, because the redox buffer is alreadyactivated. Therefore, the electrochromic materials may be allowed toconsume a greater amount of the current and thereby activate faster,increasing the speed of transmittance change.

FIG. 3 is a process flow diagram for operating an electrochromic devicewith buffer pre-activation, such as the electrochromic device 100 ofFIG. 2. The process may comprise one or more of the steps of detecting astandby triggering condition 310; initiating a buffer pre-activationvoltage 320; detecting a hibernation triggering condition 340; andsubstantially deactivating buffer 350. In some embodiments, the processmay also comprise the step of operating the electrochromic device 330.

In step 310, a standby triggering condition may be detected. A standbytriggering condition may be a condition where operation of theelectrochromic device may be required to vary the electrochromicdevice's transmittance. The standby triggering condition may be detectedby a controller comprising a processor and a memory. Further, thecontroller may be directly or indirectly connected to one or more sensorto indicate the presence of a standby condition. For example, a standbytriggering condition may comprise a starting of a vehicle, as when thevehicle is running, a user is likely to require the operation of theelectrochromic device. Additionally, the occupancy of the vehicle mayconstitute a standby triggering condition as electrochromic deviceoperation is more likely to be required when the vehicle is occupied.Accordingly, the controller, for example, may sense the presence of astandby triggering condition by connection to the vehicle's ignition orCAN, a weight sensor, and/or an imager.

In step 320, a buffer pre-activation voltage may be initiated. Thebuffer pre-activation voltage may be initiated by the controller based,at least in part, on the detection of the standby triggering condition.Accordingly, the controller may initiate the buffer pre-activationvoltage by delivering an electrical potential across two electrodes ofthe electrochromic device. The buffer pre-activation voltage may enablethe electrochromic device to enter a standby ready state where thebuffer in the electrochromic medium is a least partially activated,thereby allowing for faster and more responsive device performance whena change in transmittance is commanded. In some embodiments, the buffermay be fully activated. Additionally, in some embodiments, the bufferpre-activation voltage may not substantially activate the electrochromicmaterials. Accordingly, the electrochromic materials my exhibit anactivation percentage of less than or equal to 20, 15, 10, 5, 4, 3, 2,or 1 percent due to application of the buffer pre-activation voltage.

In step 330, the electrochromic device may be operated. The operation ofthe electrochromic device may include varying the transmittance of theelectrochromic materials in the device. Accordingly, this is the stepwhere the device is actually used with the benefit of the faster andmore responsive performance due to the buffer pre-activation. Thisoperation may be carried out by the controller, which may in turn changethe electrical potential across the two electrodes of the electrochromicdevice.

In step 340, a hibernation triggering condition may be detected. Ahibernation triggering condition may be a condition where a potentialneed for the electrochromic device is likely no longer present. Thehibernation triggering condition may be detected directly or indirectlyby the controller via one or more sensor. In some embodiments, thehibernation triggering condition may comprise the removal of the standbytriggering condition. For example, the hibernation triggering conditionmay be the turning off the vehicle or the absence of an occupancy forthe vehicle. Accordingly, the controller, for example, may detect thepresence of a hibernation triggering condition by removal of a key,connection to a vehicle's CAN, weight sensors, or imagers. Turning offthe vehicle or removing a key, for example, may signify that the vehicleis no longer being driven and therefore variable transmittanceoperations are no longer required. Likewise, sensing via weight sensors,imagers, or other means may be used to determine the vehicle is notoccupied and therefore that variable transmittance operations are nolonger required.

In step 350, the buffer may be substantially deactivated. The buffer maybe substantially deactivated by the controller based, at least in part,on the detection of the hibernation triggering condition. Accordingly,the controller may deactivate the buffer by reducing the electricalpotential across the two electrodes of the electrochromic device to avalue substantially below the buffer's activation potential.Additionally, in such as state, the electrochromic materials may also besubstantially de-activated.

Embodiments of the present disclosure may have the advantages of devicedurability and energy savings, while reaping the benefits of the bufferpre-activation. First, applying a buffer pre-activation voltage to theelectrochromic solution may require power. Accordingly, by eliminatingthe buffer pre-activation voltage application when the electrochromicproperties of the device are not likely to be needed, energy is saved.Second, electrochromic materials sometimes do not adequately return to apredetermined state during normal operation. Further, in someinstances—even in the absence of an electrical potential—anodic andcathodic materials of the electrochromic medium may partially oxidize orreduce, respectively. This reduction and oxidation may result in anundesirable residual coloration of the electrochromic medium. Theseoxidations and reductions are mitigated by the presence of a redoxbuffer in the electrochromic medium.

FIG. 4a is a process flowchart for operating an electrochromic devicewith buffer pre-activation, such as the electrochromic device 100 ofFIG. 2. The process of operating the electrochromic device with bufferpre-activation comprises the steps of: initiating a bufferpre-activation voltage 400, holding the buffer pre-activation voltage410, increasing to an electrochromic medium activation voltage 420, andholding the electrochromic medium activation voltage 430. These andother steps of the process depicted in FIG. 4a may be accomplished by acontroller, directly or indirectly, applying, increasing, decreasing, orholding an electrical potential or voltage across two electrodes of theelectrochromic device. Further, holding a voltage may take variousforms. Holding a voltage, for example, may be done by the controllerconstantly applying, oscillating, or pulsing a voltage across theelectrodes, such that an overall activation or deactivation is generallymaintained at a level.

Step 400 depicts the first step of initiating a buffer pre-activationvoltage. This voltage is responsible for activating the electrochromicmedium such that the buffer's requirement for additional current foractivation is substantially reduced or eliminated, thereby allowingsubsequent activation current to go more substantially towards theelectrochromic material activation. However, while the bufferpre-activation voltage is intended to activate the buffer, there may besome collateral electrochromic material activation as well. Thiscollateral electrochromic material activation may possibly lead to adecrease in the electrochromic device's high-end transmittance. However,in some embodiments, the electrochromic material activation may not besubstantial, despite any collateral activation. Accordingly, theelectrochromic materials my exhibit an activation percentage of lessthan or equal to 20, 15, 10, 5, 4, 3, 2, or 1 percent due to applicationof the buffer pre-activation voltage.

In some embodiments, this buffer pre-activation voltage may be equal tothe activation potential of the buffer. However, the bufferpre-activation voltage may also be less than or greater than theactivation potential of the buffer. If the buffer pre-activation voltageis less than the buffer activation potential, the buffer may be onlypartially pre-activate and the electrochromic material activation lagmay be greater than if the buffer were fully activated, but less than ifthere was no buffer pre-activation voltage applied to the electrochromicmedium. If the buffer pre-activation voltage is more than the bufferactivation potential, the buffer may fully pre-activate, but the degreeof electrochromic material activation of the stand-by state mayincrease, effectively reducing the dynamic range of the electrochromicdevice on the high transmittance end. In particular, the bufferpre-activation voltage may be at or about 0.10, 0.15, 0.20, 0.25, 0.30,0.35, 0.40, 0.45, 0.50, or 0.55 volts.

Step 410 depicts the subsequent step of holding the bufferpre-activation voltage to maintain buffer pre-activation. Accordingly,the overall activation of the buffer may generally be maintained at thesame level.

Step 420 depicts the next step of the process, wherein the voltage maybe increased to an electrochromic activation voltage to substantiallyactivate the electrochromic materials. Accordingly, the activation ofthe electrochromic materials may be substantially increased. The voltageof the electrochromic activation voltage may be determined by the degreeof desired light transmission.

Step 430 depicts holding the electrochromic activation voltage tomaintain a corresponding level of electrochromic material activation.The electrochromic activation voltage will be held for as long as thelevel of electrochromic activation—or in other words, devicedarkening—is desired. Holding the voltage, for example, may be done suchthat the overall activation is generally maintained at the same level.

In some embodiments, the process of operating the electrochromic devicewith buffer pre-activation may further comprise one or more of the stepsof: reducing the applied voltage to an electrochromic deactivationvoltage 440, holding the electrochromic deactivation voltage 450,increasing to the buffer pre-activation voltage 460, and holding thebuffer pre-activation voltage 410.

In step 440, the voltage may be reduced to an electrochromicde-activation voltage. The electrochromic de-activation voltage may beopposite in sign (i.e. positive or negative) of the bufferpre-activation and electrochromic activation voltages, thereby speedingup the de-activation of the electrochromic materials. Further, theelectrochromic de-activation voltage may equal the buffer pre-activationvoltage in magnitude. For example, the buffer de-activation voltage maybe at or about −0.10, −0.15, −0.20, −0.25, −0.30, −0.35, −0.40, −0.45,−0.50, or −0.55 volts. Additionally, the electrochromic de-activationvoltage may be operable to substantially de-activate the electrochromicmaterials and/or the buffer.

Subsequently, in step 450, the electrochromic deactivation voltage maybe held. This voltage may be held to continue the electrochromicmaterial deactivation until the desired level of deactivation of theelectrochromic materials and/or buffer is achieved. Further, theelectrochromic deactivation voltage may be held such that the overallde-activation rate is generally maintained.

Next, in step 460, the applied voltage may be increased back to a bufferpre-activation voltage. Increasing the voltage back to the bufferpre-activation voltage thereby returns the device back to the stand-bystate. In some embodiments, the buffer pre-activation voltage of step460 is equal to the buffer pre-activation voltage of step 400, however,the buffer pre-activation voltages may be different.

Additionally, in embodiments not comprising steps 440, 450, and/or 460,after step 430, wherein the electrochromic activation voltage is held,the process may proceed to step 435 where the voltage may be reduced toa buffer pre-activation voltage. Accordingly, the electrochromic mediummay be returned a to a stand-by state where the buffer is pre-activated.Following the reduction of the voltage to the buffer pre-activationvoltage in step 435, the process may additionally proceed back to step410 where the buffer pre-activation voltage may be held.

Advantageously, in some embodiments, the electrochromic device operationprocess with buffer pre-activation may further comprise step 437. Instep 437, the voltage may be changed to an auxiliary voltage. Theauxiliary voltage may correspond to a different level of electrochromicmaterial activation or device darkening. Additionally, in someembodiments, after changing to the auxiliary voltage of step 437, theprocess may further proceed to step 439, wherein the auxiliary voltageis held for as long as the auxiliary state is desired. Further, in someembodiments, step 439 may loop back to step 437 enabling additionalauxiliary states. Furthermore, in some embodiments, these auxiliarystate steps may then proceed to, and take advantage of, the processsteps of 440, 450, and/or 460. Alternatively, it is contemplated thatstep 439 may proceed to the stand-by sate directly through step 435,without the benefit of steps 440, 450, and/or 460.

Some embodiments of the present disclosure may have the advantages offaster and more responsive electrochromic device transmittance changes.Additionally, process steps 440, 450, and 460 increase the deactivationrate when returning to the standby pre-activated buffer stage, likewiseproviding faster and more responsive device transmittance changes, aswell. Further, the addition of steps 437 and 439 may thereby allow thedevice to be further adaptive and change to various states of darkeningdue to ever changing conditions, without the need to revert all the wayback to the buffer pre-activated stand-by state of step 410.

FIG. 4b is a voltage diagram depicting the voltage stages of anembodiment of the process outlined in FIG. 4a , over time. However, FIG.4b is merely a schematic graph depicting the rise and fall relationshipof the various stages in terms of voltage, and as such, the relativemagnitudes and durations are for illustrative purposes only. Further,the transitions from one voltage to another may not be perfectlystepwise as depicted and may actually comprise smoothed-out transitionsfrom one voltage to another.

Section 400 depicts the first step of initiating a buffer pre-activationvoltage. This voltage may be responsible for activating the buffer suchthat the buffer no longer requires activation, thereby allowingsubsequent activation to go more substantially towards theelectrochromic materials. However, while the buffer pre-activationvoltage is intended to activate the buffer, there may be some collateralelectrochromic material activation, as well.

In some embodiments, this buffer pre-activation voltage is equal to theactivation potential of the buffer. However, the buffer pre-activationvoltage may be less than or greater to the activation potential of thebuffer. If the buffer pre-activation voltage is less than the bufferactivation potential, the buffer may only partially pre-activate and theelectrochromic material activation lag may be be greater than if thebuffer were fully activated, but less than if there was no bufferpre-activation voltage applied to the electrochromic medium. If thebuffer pre-activation voltage is more than the buffer activationpotential, the buffer may be fully pre-activated, but the degree ofelectrochromic material activation of the stand-by state may beincreased, effectively reducing the dynamic range of the electrochromicdevice on the high transmittance end. In particular, the bufferpre-activation voltage may be at or about 0.10, 0.15, 0.20, 0.25, 0.30,0.35, 0.40, 0.45, 0.50, or 0.55 volts.

Section 410 depicts the subsequent step of holding the bufferpre-activation voltage to maintain buffer pre-activation. Further,holding a voltage may take various forms. Holding a voltage, forexample, may be done by constantly applying, oscillating, or pulsing avoltage, such that the overall activation is generally maintained at thesame level. Accordingly, the overall activation of the buffer maygenerally be maintained at the same level.

Section 420 depicts the next step of the process. In section 420, thevoltage is increased to an electrochromic activation voltage to activatethe electrochromic medium. The voltage to which the electrochromicmedium activation voltage is increased will be determined by the degreeof desired light transmission.

Section 430 depicts holding the electrochromic activation voltage tomaintain the corresponding level of electrochromic activation. Theelectrochromic medium activation voltage will be held for as long as thelevel of electrochromic activation—or in other words, devicedarkening—is desired. Holding the voltage, for example, may be done,such that the overall activation is generally maintained at the samelevel.

Sections 440, 450, and 460 depict the steps of: lowering to anelectrochromic deactivation voltage 440, holding the electrochromicmedium deactivation voltage 450, and increasing to the bufferpre-activation voltage 460.

In section 440, the voltage is reduced to an electrochromicde-activation voltage, wherein the electrochromic de-activation voltageis opposite in polarity (i.e. positive or negative) relative the bufferpre-activation and electrochromic activation voltages, thereby speedingup the de-activation of the electrochromic materials. Further, while theelectrochromic de-activation voltage is opposite in polarity, in someembodiments, it may be equal to the buffer pre-activation voltage inmagnitude. In particular, the buffer de-activation voltage may be at orabout −0.10, −0.15, −0.20, −0.25, −0.30, −0.35, −0.40, −0.45, −0.50, or−0.55 volts.

In section 450, the electrochromic deactivation voltage is held. Thisvoltage is held for the purpose of continuing the electrochromicmaterial deactivation until the desired level of deactivation isachieved. Further, the electrochromic deactivation voltage may be heldsuch that the overall de-activation rate is generally maintained.

In section 460, the applied voltage is increased back to a bufferpre-activation voltage. Increasing the voltage back to the bufferpre-activation voltage thereby returns the device back to the stand-bystate, wherein the buffer is held in a pre-activated state.

Additionally, section 435 represents the alternative pathway of reducingthe voltage to the buffer pre-activation voltage and not takingadvantage of the steps of lowering to an electrochromic deactivationvoltage, holding the electrochromic medium deactivation voltage, andincreasing to the buffer pre-activation voltage.

FIG. 5 depicts an exemplary schematic of the percent transmission oflight as a function of voltage applied to an electrochromic medium. Asline 500 shows, the percent transmission of light—or in other words, theamount of darkening of the electrochromic materials—is directly relatedto the voltage applied thereto. Accordingly, this relationship, whichwill vary depending on the electrochromic materials used, will determinethe electrochromic activation voltage needed to achieve a desired degreeof darkening.

FIG. 6 depicts a schematic graph comparing light transmission as afunction of time with and without buffer pre-activation. Line 610 plotsthe transmission of an electrochromic medium over time when there is nobuffer pre-activation voltage applied and held prior. Conversely, line610 plots the transmission of the electrochromic medium when the bufferpre-activation voltage was previously initiated and held to pre-activatethe electrochromic medium into a standby state. Electrochromic mediumtransmission is decreasing for these lines, accordingly, this graphrepresents electrochromic material darkening.

These plots show that when the buffer is pre-activated into a standbystate, the electrochromic device approaches its dimmed state faster.This is advantageous for faster response time, however, it comes at thecost of reduced dynamic range on the high transmission end, as shown bythe reduced transmittance of 610 at the zero-time starting point. Thisreduction of dynamic range is the result of collateral electrochromicmaterial activation during the application of the buffer pre-activationvoltage.

FIG. 7 is a schematic graph showing the absolute rate of change intransmission of the electrochromic solution as a function of time. Inother words, FIG. 7 shows how fast the electrochromic device isdarkening, when a darkening voltage is applied. Plot 700 is the rate ofchange of the electrochromic medium when the buffer was notpre-activated prior applying the electrochromic activation voltage.Conversely, plot 710 is the rate of change of the electrochromic mediumwhen the buffer is pre-activated prior to the electrochromic activationvoltage application.

These plots demonstrate the effect and related advantage of activatingthe buffer prior to darkening. At the start of the darkening, when thebuffer is not pre-activated, the electrochromic materials activate moreslowly, represented by the initial upward slope of plot 700. This isbecause the buffer was not pre-activated, therefore, the bufferactivation is taking place during this stage, consuming availableelectrical current and thereby reducing the current available forelectrochromic material activation. However, this penalty isincreasingly reduced as the buffer is increasingly activated, accountingfor the upward slope. Further, the peak of plot 700 represents the pointat which the buffer has become activated and therefore no longer hasincreased consumption of current, current which is needed by theelectrochromic materials. Plot 710 starts at its high point in ratebecause the buffer was already activated, thereby there is no reductionin available current for electrochromic material activation at the startof the darkening. Further, the plots show that after the peak, the tworates are substantially parallel to each other, with plot 700 beingdelayed in time. Therefore, the activation of the buffer prior to thedarkening phase has the benefit of a more responsive system wherein theeffect of applying and holding the electrochromic activation voltage canmore readily be observed by an operator of the electrochromic device.

In the appending claims, voltages may be referred to as a first voltage,second voltage, third voltage, etc., but the denotation of first,second, third, etc. serves only to distinguish one entity or action fromanother entity or action, without necessarily requiring or implying anysuch actual relationship or order between such entities or actions. Forexample, a first voltage may refer to a buffer pre-activation voltage oran electrochromic medium activation voltage, depending on thecircumstances of the claim and which parts of the process are beingclaimed. Accordingly, in this document, relational terms, such as“first,” “second,” and the like, are used solely to distinguish oneentity or action from another entity or action, without necessarilyrequiring or implying any actual such relationship or order between suchentities or actions.

As used herein, the term “and/or,” when used in a list of two or moreitems, means that any one of the listed items can be employed by itself,or any combination of the two or more of the listed items can beemployed. For example, if a composition is described as containingcomponents A, B, and/or C, the composition can contain A alone; B alone;C alone; A and B in combination; A and C in combination; A and C incombination; B and C in combination; or A, B, and C in combination.

The term “substantially,” and variations thereof, will be understood bypersons of ordinary skill in the art as describing a feature that isequal or approximately equal to a value or description. For example, a“substantially planar” surface is intended to denote a surface that isplanar or approximately planar. Moreover, “substantially” is intended todenote that two values are equal or approximately equal. If there areuses of the term which are not clear to persons of ordinary skill in theart, given the context in which it is used, “substantially” may denotevalues within about 10% of each other, such as within about 5% of eachother, or within about 2% of each other.

As used herein, “about” will be understood by persons of ordinary skillin the art and will vary to some extent depending upon the context inwhich it is used. If there are uses of the term which are not clear topersons of ordinary skill in the art, given the context in which it isused, “about” will mean up to plus or minus 10% of the particular term.

For purposes of this disclosure, the term “associated” generally meansthe joining of two components (electrical or mechanical) directly orindirectly to one another. Such joining may be stationary in nature ormovable in nature. Such joining may be achieved with the two components(electrical or mechanical) and any additional intermediate members beingintegrally formed as a single unitary body with one another or with thetwo components. Such joining may be permanent in nature or may beremovable or releasable in nature unless otherwise stated.

The terms “including,” “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements, but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. An element preceded by “comprises a . . . ” does not, withoutmore constraints, preclude the existence of additional identicalelements in the process, method, article, or apparatus that comprisesthe elements.

It will be understood that any described processes or steps withindescribed processes may be combined with other disclosed processes orsteps to form structures within the scope of the present invention. Theexemplary structures and processes disclosed herein are for illustrativepurposes and are not to be construed as limiting.

It is to be understood that although several embodiments are describedin the present disclosure, numerous variations, alterations,transformations, and modifications may be understood by one skilled inthe art, and the present disclosure is intended to encompass thesevariations, alterations, transformations, and modifications as withinthe scope of the appended claims, unless their language expressly statesotherwise.

What is claimed is:
 1. A device comprising: a first substrate having afirst surface and a second surface; a second substrate having a thirdsurface and a fourth surface, the second substrate disposed in aspaced-apart relationship with the first substrate; a first electrodedisposed on the second surface; a second electrode disposed the thirdsurface; and an electrochromic medium disposed between the first andsecond electrodes, the electrochromic medium comprising electrochromicmaterials and a redox buffer, the electrochromic materials and buffereach operable between activated and deactivated states; wherein thefirst and second electrodes are operable to: initiate a first voltage,the first voltage operable to substantially activate the buffer; holdthe first voltage, holding the first voltage operable to maintain thesubstantial buffer activation; initiate a second voltage greater thanthe first voltage, the second voltage having the same polarity as thefirst voltage, and the second voltage operable to substantially increasethe degree of activation of the electrochromic materials; and hold thesecond voltage, holding the second voltage operable to maintain theincreased electrochromic material activation.
 2. The device of claim 1,wherein the first and second electrodes are further operable to:initiate a third voltage, wherein the third voltage is opposite inpolarity relative the first and second voltages; hold the third voltage,wherein holding the third voltage is operable to substantiallyde-activate the electrochromic materials; initiate a fourth voltage,wherein the fourth voltage is of the same polarity as the first andsecond voltages, and the fourth voltage is operable to substantiallyactivate the buffer; and hold the fourth voltage, wherein holding thefourth voltage is operable to maintain the buffer in a substantiallyactivated state.
 3. The device of claim 2, wherein the first and thirdvoltages are equal in absolute magnitude.
 4. The device of claim 2,wherein the fourth voltage is substantially equal to the first voltage.5. The device of claim 1, wherein the first voltage is not operable tosubstantially activate the electrochromic materials.
 6. The device ofclaim 2, wherein the fourth voltage is not operable to substantiallyactivate the electrochromic materials.
 7. The device of claim 1, whereinthe first and second electrodes are further operable to: initiate athird voltage, the third voltage operable to substantially change thedegree of activation of the electrochromic materials, the third voltagebeing different from the first voltage; and hold the third voltage,holding the third voltage operable to maintain activation of theelectrochromic materials.
 8. The device of claim 7, wherein the firstand second electrodes are further operable to: initiate a fourthvoltage, the fourth voltage opposite in polarity relative the first,second, and third voltages; hold the fourth voltage, wherein holding thefourth voltage is operable to substantially de-activate theelectrochromic materials; initiate a fifth voltage, wherein the fifthvoltage is of the same polarity as the first, second, and thirdvoltages, and the fifth voltage is operable to substantially activatethe buffer; and hold the fifth voltage, wherein holding the fifthvoltage is operable to maintain the buffer in an activated state.
 9. Thedevice of claim 8, wherein the fifth voltage is not operable tosubstantially activate the electrochromic materials.
 10. The device ofclaim 1, wherein: the device is disposed in a vehicle and operable toreceive a signal from an imager operable to detect an occupancy of thevehicle; and the first and second electrodes are operable to initiatethe first voltage based, at least in part, on detecting the occupancy ofthe vehicle.
 11. The device of claim 1, wherein the device is associatedwith a vehicle and operable to receive a signal from a sensor associatedwith the vehicle, the signal corresponding to the detection of a standbytriggering condition by the sensor.
 12. The device of claim 11, whereinthe first and second electrodes are operable to initiate the firstvoltage based, at least in part, on the detection of the standbytriggering condition.
 13. The device of claim 11, wherein the device isoperable to substantially deactivate the buffer when the signal is nolonger received.
 14. The device of claim 1, wherein: the device isassociated with a vehicle and operable to receive a signal from a sensorassociated with the vehicle, the signal corresponding to the detectionof a hibernation triggering condition by the sensor; and the first andsecond electrodes are further operable to substantially stop voltageapplication to the electrochromic medium based, at least in part, on thereceived signal.
 15. A method comprising: initiating a first voltageapplied to an electrochromic medium, the electrochromic mediumcomprising electrochromic materials and a redox buffer, theelectrochromic materials and buffer each electroactive and operablebetween activated and deactivated states, the first voltage operable tosubstantially activate the buffer and not substantially activate theelectrochromic materials; holding the first voltage, wherein holding thefirst voltage is operable to maintain the buffer in a substantiallyactivated state; initiating a second voltage applied to theelectrochromic medium, the second voltage operable to substantiallyincrease the degree of the electrochromic materials' activation, and thesecond voltage greater than the first voltage; and holding the secondvoltage, wherein holding the second voltage is operable to maintain theincreased electrochromic materials' activation.
 16. The method of claim15, further comprising: lowering the second voltage to a third voltage,wherein the third voltage is opposite in sign as the first and secondvoltages; holding the third voltage, wherein holding the third voltageis operable to substantially de-activate the electrochromic materials;increasing the third voltage to a fourth voltage, wherein the fourthvoltage is of the same sign as the first and second voltages, and thefourth voltage is operable to substantially activate the buffer and notsubstantially activate the electrochromic materials; and holding thefourth voltage, wherein holding the fourth voltage is operable tomaintain the buffer in a substantially activated state.
 17. A systemcomprising: an electrochromic device comprising an electrochromicmedium, the electrochromic medium comprising electrochromic materialsand a redox buffer; and a controller operable to: initiate a firstvoltage across the electrochromic medium, the first voltage operable tosubstantially activate the buffer; hold the first voltage, whereinholding the first voltage is operable to substantially maintain thebuffer activation; initiate a second voltage across the electrochromicmedium, the second voltage greater than the first voltage, and thesecond voltage operable to substantially increase an activation state ofthe electrochromic materials; and hold the second voltage, holding thesecond voltage operable to maintain the increased activation of theelectrochromic materials.
 18. The system of claim 17, furthercomprising: a first sensor, operable to detect a standby triggeringcondition; wherein the controller is further operable to: receive asignal from the sensor, the signal corresponding to the detection of thestandby triggering condition, and based, at least in part, on thedetection of the standby triggering condition, initiate the firstvoltage.
 19. The system of claim 18, wherein: at least one of the firstsensor and a second sensor are operable to detect a hibernationtriggering condition; and the controller is further operable to: receivea second signal from the at least one of the first sensor and the secondsensor, the second signal corresponding to the detection of thehibernation triggering condition; and based, at least in part, on thereceipt of the second signal, initiate a third voltage operable tosubstantially deactivate the buffer.
 20. The device of claim 18, whereinthe standby triggering condition is at least one of a vehicle startingand a vehicle occupancy.